Exit in an orderly fashion
I hear this song constantly, most recently last week: migrating off a US cloud to a European cloud is impossible because of stack complexity.
Not some SaaS company with a tidy AWS stack. Airbus – the people who make machines that carry hundreds of humans through the sky at 900 km/h and aren't allowed to get the software wrong. They just pulled 70 critical applications off of Amazon’s servers and dropped them onto Scaleway, a French cloud provider, with more to follow. They migrated the whole nervous system of an aerospace giant.
Understandably, they didn't want that data anywhere within reach of a US government that keeps demonstrating that "trust us" isn't security architecture. Was it as simple as switching phone provider? Probably not. Worth it? Definitely.
So, next time you hear cloud sovereignty is a nice idea for people who don't have real infrastructure, point them at a company that manufactures literal airliners.
Colin